function sigmin = pseudo(A, x, y)
  N = size(A,1);
  nx = length(x);
  ny = length(y);
  maxit = 100;
  T = schur(complex(A));
  sigmin = zeros(ny, nx)
  for k = 1:nx, for j = 1:ny
      T1 = (x(k)+y(j)*1i)*eye(N) - T; T2 = T1'
      sigold = 0; qold = zeros(N,1); beta = 0; H = []
      q = randn(N,1) + 1i*randn(N,1); q = q / norm(q);
      for p = 1:maxit
	v = T1\(T2\q) - beta*qold;
	alpha = real(q'*v); v = v - alpha*q;
	beta = norm(v); qold = q; q = v/beta;
	H(p+1,p) = beta; H(p, p+1) = beta; H(p,p) = alpha;
	sig = max(eig(H(1:p, 1:p)));
	if abs(sigold/sig - 1) < 1e-3
	  break;
	endif
	sigold = sig;
      endfor
      sigmin(j,k) = sqrt(sig);
      
    endfor
  endfor
  return;
endfunction
    